1. Field of the Invention
The present invention relates to a speed change operation mechanism, and particularly to a dual-bearing reel speed change operation mechanism for switchably transmitting handle rotation to a spool at either a high speed or a low speed.
2. Background Art
Japan Laid-open Patent Application Publication No. H07-039413 (Y2) describes an exemplary dual-bearing reel embedded with a rotation transmission mechanism configured to transmit handle rotation to a spool. The rotation transmission mechanism includes a speed change mechanism configured to switch handle rotation between a high speed and a low speed. In the speed change mechanism, a high speed gear with a large diameter and a low speed gear with a small diameter are attached onto the distal end of a handle shaft. Either of the high speed gear and the low speed gear is selectively allowed to unitarily rotate with the handle shaft. Further, a pinion gear with a small diameter and a pinion gear with a large diameter are attached to a spool shaft and a spool while being unitarily rotatable therewith. The small-diameter pinion gear is allowed to mesh with the large-diameter high speed gear, whereas the large-diameter pinion gear is allowed to mesh with the small-diameter low speed gear. In conjunction with a press operation of an operating shaft, rotation transmission from the handle shaft to the high speed gear is configured to be switched to rotation transmission from the handle shaft to the low speed gear. When the operating shaft is pressed inwards, handle rotation is transmitted to the low speed gear through the handle shaft and is further transmitted to the large-diameter pinion gear through the low speed gear. The spool shaft and the spool hereby rotated at a low speed. On the other hand, handle rotation is transmitted to the high speed gear through the handle shaft and is further transmitted to the small-diameter pinion gear through the high speed gear when the operating shaft is pulled outwards by an operation of moving a lock member, which is movably disposed onto the handle arm, in a direction away from a lock groove formed on the operating shaft. The spool shaft and the spool are thereby rotated at a high speed.
In the speed change operation mechanisms of the aforementioned type, the operating shaft is generally configured to be pulled outwards by an operation of moving the lock member, which is movably disposed onto the handle arm, in a direction away from the lock groove formed on the operating shaft (see e.g., http://fservice.shimano.co.jp/parts/pdf/02030.pdf). The speed change operation mechanisms of the aforementioned type include a base member (retainer), a lock member (lock plate) and a coil spring. The base member is a plate member disposed onto a handle arm. The lock member is a plate member including an operating knob and a locking portion. The operating knob is attached to the tip of the handle arm while being disposed on the base member. An angler pinches and moves the operating knob with his/her fingers. The base end of the lock portion is configured to be locked with a lock groove formed on an operating shaft. The coil spring is held by a protrusion protruding from the base member. Under the condition, the coil spring is configured to urge the lock portion of the lock member towards the lock groove formed on the operating shaft. Further, the base member includes a guide groove thereon for guiding and moving the lock member in a predetermined direction.